The present invention relates to a memory unit and a data processing unit and method for using a memory unit as a medium for recording, for example, audio data, the memory unit being attachable to the data processing unit and detachable therefrom.
Electrically Erasable Programmable Read-Only Memory (xe2x80x9cEEPROMxe2x80x9d) is electrically rewritable memory that requires a relatively large physical space because each bit of memory storage is composed of two transistors. Thus, the integration of EEPROM is restricted. To address this problem, flash memory capable of storing one bit with one transistor using an all-bit-erase system was developed. Flash memory may become a successor of recording media such as magnetic disks and optical discs, and may be used in memory cards that can be freely attached to an apparatus and detached therefrom. A digital audio recorder/player may use such a memory card instead of a Compact Disc(trademark) (xe2x80x9cCDxe2x80x9d) or Mini Disc(trademark) (xe2x80x9cMDxe2x80x9d).
When an audio recorder using such a memory card employs a data compressing method that allows digital audio data to be recorded/reproduced in a relatively high quality, copyrights on music titles which can be recorded and reproduced thereby need to be protected. As an example, encrypting technologies may be used to prohibit unauthorized memory cards from such recording/reproducing. In other words, an authorized recorder/player matched with an authorized memory card are required to decrypt encrypted data. In addition to copyright protection, encrypting technologies may be used to protect the security of information stored in a memory card.
However, memory cards may not include any encrypting function. Thus, when secret data is to be recorded to such a memory card, the data is encrypted by the recorder/player before being recorded to the memory card. There are two problems with such a technique. First, if a decryption key is stored in the memory card, the security of data is not maintained. Second, if the decryption key is stored in the recorder/player, encrypted data can only be decrypted by the predetermined recorder/player that encrypted and recorded the data. Consequently, the memory card storing the encrypted data would not be compatible with other recorders/players. In other words, if data encrypted by a predetermined recorder/player is stored in a memory card, the encrypted data stored in the memory card cannot be decrypted by other recorders/players. To address this problem, a system where both a recorder/player and a memory card include an encrypting function, and where they are mutually authenticated is proposed. With such a system, both the security and compatibility of cards can be maintained.
In reality, non-copyrighted data is sometimes recorded to a memory card and reproduced therefrom. For example, when a conversation is recorded, an audio compressing method with a high compression ratio may be used, even though the decompressed audio quality would be relatively low. In such a case, it is not necessary to protect any copyrights on the recorded data. Additionally, when a memory card is used as a medium for recording a picture photographed by an electronic still camera, a video camera, or the like, it may likewise be unnecessary to protect any copyrights on the recorded video data.
A security type memory card having an encrypting function may be more expensive than a non-security type memory card. Thus, depending on the necessity for copyright protection and security, it is expected that a security type memory card and a non-security type memory card will be selectively used.
When there are two types, a security type and a non-security type, of recorders/players and memory cards, respectively, it may be necessary to determine whether each of a recorder/player and a memory card used is of the security type or the non-security type to ensure compatibility. Alternatively, the shape of a security type memory card may be different from that of a non-security type memory card. For example, a notch may be formed on a security type memory card or a non-security type memory card to prevent it from being attached to a non-security type recorder/player or a security type recorder/player, respectively.
The problem with determining compatibility between a recorder/player and a memory card is that if they are not of the same type (security or non-security), the operation would be meaningless and a delay would take place. Such a situation would be a nuisance to the user. Using different shapes for the different types of memory cards may solve this problem. However, in either case, compatibility between recorders/players and memory cards is not fully provided. For instance, a security type memory card cannot be used with a non-security type or lower grade recorder/player.
An object of the present invention is to overcome the above-described problem(s) by providing a memory unit and a data processing unit and method that can determine whether a memory unit has a predetermined function or functions that is otherwise not available.
It is another object of the present invention to provide a memory unit and a data processing unit and method that can determine whether a memory unit has a security function that is otherwise not available.
It is yet another object of the present invention to provide a memory unit and a data processing unit and method that can determine whether a memory unit has a speed function that is otherwise not available.
It is still another object of the present invention to provide a security type memory card that is compatible with a non-security type recorder/player. For example, one should be able to record a picture photographed by a non-security type handy movie camera (a recording/reproducing unit with a built-in camera) to a security type memory card and reproduce the recorded picture therefrom. In such a case, the encrypting function would not be used.
It is another object of the present invention to provide a high-speed type memory card that is compatible with a non-high-speed type recorder/player. In such a case, the high-speed function would not be used.
Other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification and the drawings.
An embodiment of the present invention is a memory unit, which is attachable to/detachable from a data processing unit, having a non-volatile memory and an interface for communicating with the data processing unit; wherein identification information indicating whether the memory unit performs a predetermined function is recorded in a predetermined area of the non-volatile memory and is read by the data processing unit when the memory unit is attached to the data processing unit.
Another embodiment of the present invention is a data processing unit for recording/reproducing data to/from a memory unitxe2x80x94the memory unit having a non-volatile memory and being attachable to/detachable from the data processing unitxe2x80x94having an interface for communicating with the memory unit; wherein the data processing unit determines whether the memory unit performs a predetermined function by reading identification information recorded in a predetermined area of the memory unit.
Another embodiment of the present invention is a data processing method for use with a data processing unit for writing/reading information to/from a memory unit including: reading data from a predetermined storage area of the memory unit when the memory unit is attached to the data processing unit; and determining whether the memory unit performs a predetermined function by examining identification information stored in the predetermined area.
According to the present invention, a memory unit may have identification information which indicates whether or not the memory unit has a predetermined function recorded in a predetermined area of the memory unit. Upon attaching such a memory unit to a data processing unit, the data processing unit may read such information and determine whether the memory unit has the predetermined function.